Watlow CPC400 - Manual (Page 46)

Chapter 2: Installation CPC400 Series User’s Guide
32 Watlow Anafaze Doc. 0600-2900-2000
Wiring Control and Digital I/O
This section describes how to wire and configure the control
outputs for the CPC400 series controller. The CPC400 pro-
vides dual control outputs for each loop. These outputs can
be enabled or disabled, and are connected through a TB50
or TB18.
NOTE! Control outputs are connected to controller com-
mon when the control output is on. If you connect
external devices that may have a low side at a
voltage other than controller ground, you may
create ground loops. To prevent ground loops,
use isolated solid-state relays and isolate the
control device inputs.
Output Wiring Recommendations
When wiring output devices, use multicolored, stranded,
shielded cable for analog outputs and digital outputs con-
nected to panel-mounted solid-state relays.
• Analog outputs usually use a twisted pair.
• Digital outputs usually have 9 to 20 conductors, de-
pending on wiring technique.
Cable Tie Wraps
After you wire outputs to the TB50, install the cable tie
wraps to reduce strain on the connectors. Each row of ter-
minals has a cable tie wrap hole at one end. Thread the ca-
ble tie wrap through the cable tie wrap hole. Then, wrap
the cable tie wrap around the wires attached to that termi-
nal block.
Digital Outputs
The CPC400 provides dual control outputs for up to eight
loops. By default, heat outputs are enabled and cool out-
puts are disabled. If the heat or cool output is disabled for
a loop, then the output is available for alarms or program-
mable logic. The CPU watchdog timer output can be used
to monitor the state of the controller; see CPU Watchdog
Timer on page 35.